Bring a large pot of salted water to a boil. Preheat a grill pan. Using 8 pairs of wooden skewers, double-skewer the scallops, shrimp and cherry tomatoes. Brush with olive oil and season with salt and pepper.

Cook the pasta in the boiling water until al dente. Drain the pasta, reserving 1/2 cup of the cooking water.

Grill the kebabs over high heat until browned and cooked through, turning once, about 7 minutes.

Meanwhile, in a large skillet, melt the butter in the 2 tablespoons of olive oil. Add the shallot and garlic and cook over high heat, stirring constantly, until softened, about 2 minutes. Add the chicken broth and boil until reduced by half, about 3 minutes. Add the pasta, arugula, lemon juice and cheese to the skillet and season with salt and pepper. Toss until the arugula is slightly wilted, adding a few tablespoons of the reserved pasta water if necessary. Serve immediately with the seafood kebabs.